Vision

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Vision
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Transduction

• Conversion of one form of energy to another.

How is this important when studying sensation?
Stimulus energies to neural impulses. For
example Light energy to vision. Chemical energy
to smell and taste. Sound waves to sound.
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Vision
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We only use light energy to see.
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What makes up a light wave?
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Wavelength

• The distance from the peak of one light wave to
  the peak of the next.

• The distance determines the hue (color) of the
  light we perceive.

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Intensity
The amount of energy in a light wave. Determined
by the height of the wave. The higher the wave
the more intense the light is.
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Structure of the Eye
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Nearsighted Vision
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Farsighted Vision
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The Retina
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Feature Detection

• The concept that specific nerve cells in the
  brain respond to specific features of the
  stimulus, such as shape angle or movement.

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Familiar Face?
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Parallel Processing

• The processing of several aspects of a problem
  simultaneously.

Motion
Form
Color
Depth
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How do we see in color?
What color is this dragon?
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Color

• The dragon is anything but red.
• The dragon rejects the long wavelengths of light
  that to us are red- so red is reflected of and we
  see it.
• Also, light has no real color.
• It is our mind that perceives the color.

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Two major color theories
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Young-Helmholtz Trichromatic (three color) Theory

• Realized that any color can be created by
  combining the light waves of three primary color-

RED
GREEN
BLUE

• So they guessed that we have 3 different types of
  receptor cells in our eyes. Together they can
  pick any combination of our 7 million color
  variations.

• Most colorblind people simply lack cone receptor
  cells for one or more of these primary colors.

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Opponent-Process Theory

• We cannot see certain colors together in
  combination (red-green, blue-yellow, and
  white-black). These are antagonist/ opponent
  colors.

Tube and marble example.
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Movement AftereffectsMAEs
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Illusory Contours
Handout 12-3
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Color Effects Section
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LO 3.5 How eyes see and how eyes see colors
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Color Blindness

• A simulation for those of us who arent
• Vischeck

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Color After Effects
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Subjective Color
The moving pattern is drawn with black on white.
But if you stare at it without letting your eyes
follow the motion, you will probably see a faint
illusion of color. Part of the pattern appears to
me to be dark brown with yellowish edges. Another
part appears purplish. Different observers may
see other colors.
Fechner Color Illusion
Handout 12-5
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Psychological Properties of Sound
LO 3.6 Sound

• Wavelength interpreted as frequency or pitch
  (high, medium, or low).
• Amplitude interpreted as volume (how soft or
  loud a sound is).
• Purity interpreted as timbre (a richness in the
  tone of the sound).
• hertz (Hz) - cycles or waves per second, a
  measurement of frequency.

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LO 3.6 Sound
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LO 3.6 Sound
Sounds
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Structure of the Ear
LO 3.7 Parts of ear work together to hear
sounds

• Auditory canal - short tunnel that runs from the
  pinna to the eardrum (tympanic membrane).
• Eardrum - thin section of skin that tightly
  covers the opening into the middle part of the
  ear, just like a drum skin covers the opening in
  a drum.
• When sound waves hit the eardrum, it vibrates and
  causes three tiny bones in the middle ear to
  vibrate.
• Hammer
• Anvil
• Stirrup

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Structure of the Ear
LO 3.7 Parts of ear work together to hear
sounds

• Cochlea - snail-shaped structure of the inner ear
  that is filled with fluid.
• Organ of Corti rests in the basilar membrane
  contains receptor cells for sense of hearing.
• Auditory nerve - bundle of axons from the hair
  cells in the inner ear receives neural message
  from the organ of Corti.

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LO 3.7 Parts of ear work together to hear sounds
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LO 3.7 Parts of ear work together to hear sounds
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Theories of Pitch
LO 3.7 Parts of ear work together to hear
sounds

• Pitch - psychological experience of sound that
  corresponds to the frequency of the sound waves
  higher frequencies are perceived as higher
  pitches.
• Place theory - theory of pitch that states that
  different pitches are experienced by the
  stimulation of hair cells in different locations
  on the organ of Corti.

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Theories of Pitch
LO 3.7 Parts of ear work together to hear
sounds

• Frequency theory - theory of pitch that states
  that pitch is related to the speed of vibrations
  in the basilar membrane volley principle theory
  of pitch that states that frequencies above 100
  Hz cause the hair cells (auditory neurons) to
  fire in a volley pattern, or take turns in
  firing.
• Volley principle - theory of pitch that states
  that frequencies above 100 Hz cause the hair
  cells (auditory neurons) to fire in a volley
  pattern, or take turns in firing.

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Types of Hearing Impairments
LO 3.8 Hearing impairment

• Conduction hearing impairment - can result from
  either
• damaged eardrum (which would prevent sound waves
  from being carried into the middle ear properly),
  or
• damage to the bones of the middle ear (sounds
  cannot be conducted from the eardrum to the
  cochlea).
• Nerve hearing impairment can result from
  either
• damage in the inner ear, or
• damage in the auditory pathways and cortical
  areas of the brain.

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Surgery to Help Restore Hearing
LO 3.9 Helping people with hearing impairment

• Cochlear Implant - a microphone implanted just
  behind the ear picks up sound from the
  surrounding environment.
• Speech processor selects and arranges the sound
  picked up by the microphone.
• Implant is a transmitter and receiver, converting
  signals into electrical impulses.
• Collected by the electrode array in the cochlea
  and then sent to the brain.

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LO 3.9 Helping people with hearing impairment
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Taste
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Taste
Hmmm....lemon?
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Taste
LO 3.10 Senses of taste and smell

• Taste buds taste receptor cells in mouth
  responsible for sense of taste
• Gustation - the sensation of a taste.
• Five Basic Tastes
• Sweet
• Sour
• Salty
• Bitter
• Brothy

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LO 3.10 Senses of taste and smell
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Some tastes.not so good
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Smell
LO 3.10 Senses of taste and smell

• Olfaction (olfactory sense) sense of smell.
• Olfactory bulbs - areas of the brain located just
  above the sinus cavity and just below the frontal
  lobes that receive information from the olfactory
  receptor cells.
• At least 1,000 olfactory receptors.

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LO 3.10 Senses of taste and smell
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LO 3.10 Senses of taste and smell
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Somesthetic Senses

• Somesthetic senses - the body senses consisting
  of the skin senses, the kinesthetic sense, and
  the vestibular senses.
• Soma body
• Esthetic - feeling
• Skin senses - the sensations of touch, pressure,
  temperature, and pain.
• Sensory receptors in the skin
• Gate-control theory - pain signals must pass
  through a gate located in the spinal cord.

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A mixture of the senses - Synesthesia

• Michael Watson feels shapes when he tastes or
  smells food
• There arent enough points on the chicken. I
  wanted the taste of this chicken to be a pointed
  shape, but it came out all round.
• Carol diagnosed the severity of injury by color
• When I saw that everything was orange, I knew I
  should be rushed to the hospital.

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• Occurrence at 1 in 2000
• Females outnumber males 6 to 1
• Seems to run in families
• Hypotheses the brain architecture of
  synesthetes is different in that they are
  equipped with more connections between neurons,
  causing modularity break down.

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Amazing Touch

• Geerat Vermeij story

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• Louis Braille - 1824

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Pain? Hmmm.
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Phantom Limbs
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Cultural Differences in Pain
Hook-Swinging Ceremony - India
An illustration of hook-swinging from 1670
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Kerri Strug US Olympic Gold Medal 1996
completed last vault with sprained ankle.
Donovan McNabb threw four touchdown passes on a
broken ankle.
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LO 3.11 Sense of touch and experiencing pain
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LO 3.11 Sense of touch and experiencing pain
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LO 3.11 Sense of touch and experiencing pain
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LO 3.11 Sense of touch and experiencing pain
When people grasp two braided pipesone with cold
water running through it, the other with warm
waterthe sensation is "very hot" and painful.
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Somesthetic Senses
LO 3.12 Senses that allow body to know it is
moving and balanced

• 2. Kinesthetic sense - sense of the location of
  body parts in relation to the ground and each
  other.
• Proprioceptive receptors (proprioceptors)
• 3. Vestibular senses - the sensations of
  movement, balance, and body position sensory
  conflict theory an explanation of motion sickness
  in which the information from the eyes conflicts
  with the information from the vestibular senses,
  resulting in dizziness, nausea, and other
  physical discomforts.

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LO 3.12 Senses that allow body to know it is
moving and balanced
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Perception and Constancies
LO 3.13 Perception and perceptual constancies

• Perception - the method by which the sensations
  experienced at any given moment are interpreted
  and organized in some meaningful fashion.
• Size constancy - the tendency to interpret an
  object as always being the same actual size,
  regardless of its distance.
• Shape constancy - the tendency to interpret the
  shape of an object as being constant, even when
  its shape changes on the retina.
• Brightness constancy the tendency to perceive
  the apparent brightness of an object as the same
  even when the light conditions change.

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LO 3.13 Perception and perceptual constancies
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LO 3.13 Perception and perceptual constancies
Shape constancy
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Gestalt Principles
LO 3.14 Gestalt principles of perception

• Figureground - the tendency to perceive objects,
  or figures, as existing on a background.
• Reversible figures - visual illusions in which
  the figure and ground can be reversed.

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LO 3.14 Gestalt principles of perception
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LO 3.14 Gestalt principles of perception
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LO 3.14 Gestalt principles of perception
Do you see an old lady or a young lady?
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LO 3.14 Gestalt principles of perception
Do you see a rabbit or a duck?
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The white and black stripes on these zebras can
be reversed both can serve as either figure or
ground.
LO 3.14 Gestalt principles of perception
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Gestalt Principles
LO 3.14 Gestalt principles of perception

• Similarity - the tendency to perceive things that
  look similar to each other as being part of the
  same group.
• Proximity - the tendency to perceive objects that
  are close to each other as part of the same
  grouping.
• Closure - the tendency to complete figures that
  are incomplete.
• Continuity - the tendency to perceive things as
  simply as possible with a continuous pattern
  rather than with a complex, broken-up pattern.
• Contiguity - the tendency to perceive two things
  that happen close together in time as being
  related.

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LO 3.14 Gestalt principles of perception
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Depth Perception
LO 3.15 Perceiving the world in three dimensions

• Depth perception - the ability to perceive the
  world in three dimensions.
• Studies of depth perception
• Visual cliff experiment

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LO 3.15 Perceiving the world in three dimensions
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Monocular Cues
LO 3.15 Perceiving the world in three dimensions

• Monocular cues (pictorial depth cues) cues for
  perceiving depth based on one eye only.
• Linear perspective the tendency for parallel
  lines to appear to converge on each other.
• Relative size - perception that occurs when
  objects that a person expects to be of a certain
  size appear to be small and are, therefore,
  assumed to be much farther away.
• Interposition (overlap) - the assumption that an
  object that appears to be blocking part of
  another object is in front of the second object
  and closer to the viewer.

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Monocular Cues
LO 3.15 Perceiving the world in three dimensions

1. Aerial perspective - the haziness that surrounds
   objects that are farther away from the viewer,
   causing the distance to be perceived as greater.
2. Texture gradient - the tendency for textured
   surfaces to appear to become smaller and finer as
   distance from the viewer increases.
3. Motion parallax - the perception of motion of
   objects in which close objects appear to move
   more quickly than objects that are farther away.
4. Accommodation - as a monocular clue, the brains
   use of information about the changing thickness
   of the lens of the eye in response to looking at
   objects that are close or far away.

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LO 3.15 Perceiving the world in three dimensions
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LO 3.15 Perceiving the world in three dimensions
Pictorial depth cues
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LO 3.15 Perceiving the world in three dimensions
Linear Perspective
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Binocular Cues
LO 3.15 Perceiving the world in three dimensions

• Binocular cues - cues for perceiving depth based
  on both eyes.
• Convergence - the rotation of the two eyes in
  their sockets to focus on a single object,
  resulting in greater convergence for closer
  objects and lesser convergence if objects are
  distant.
• Binocular disparity - the difference in images
  between the two eyes, which is greater for
  objects that are close and smaller for distant
  objects.

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Perceptual Illusions
LO 3.16 Visual illusions

• Müller-Lyer illusion - illusion of line length
  that is distorted by inward-turning or
  outward-turning corners on the ends of the lines,
  causing lines of equal length to appear to be
  different.
• Moon illusion the moon on the horizon appears
  to be larger than the moon in the sky.
• Apparent distance hypothesis
• Illusions of Motion
• autokinetic effect - a small, stationary light in
  a darkened room will appear to move or drift
  because there are no surrounding cues to indicate
  that the light is not moving.
• stroboscopic motion - seen in motion pictures, in
  which a rapid series of still pictures will
  appear to be in motion.
• phi phenomenon lights turned on in a sequence
  appear to move.

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LO 3.16 Visual illusions
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LO 3.16 Visual illusions
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LO 3.16 Visual illusions
Ames room illusion
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LO 3.16 Visual illusions
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Factors that Influence Perception
LO 3.17 Factors that influence perception

• Perceptual set (perceptual expectancy) - the
  tendency to perceive things a certain way because
  previous experiences or expectations influence
  those perceptions.
• Top-down processing - the use of preexisting
  knowledge to organize individual features into a
  unified whole.
• Bottom-up processing - the analysis of the
  smaller features to build up to a complete
  perception.

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LO 3.17 Factors that influence perception
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LO 3.17 Factors that influence perception
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Applying Psychology
LO 3.17 Factors that influence perception

• Extrasensory Perception (ESP) - claim of
  perception that occurs without the use of normal
  sensory channels such as sight, hearing, touch,
  taste, or smell.
• Telepathy - claimed ability to read another
  persons thoughts, or mind reading.
• Clairvoyance - supposed ability to see things
  that are not actually present.
• Precognition - supposed ability to know something
  in advance of its occurrence or to predict a
  future event.
• Parapsychology - the study of ESP, ghosts, and
  other subjects that do not normally fall into the
  realm of ordinary psychology.

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LO 3.17 Factors that influence perception
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